Did you know?

Click any word in a definition or example to find the entry for that word

arch - definition and synonyms

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.

Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

noun [countable]     arch pronunciation in American English
Word Forms
  1. 1
    a curved structure at the top of a door, window, or gate

    the arch above the front door

    1. a.
      a structure with a curved top and two straight sides that you can walk through

      a garden arch

    2. b.
      a curved structure, especially one that supports a building or a bridge

      Many people sheltered under the arches of the bridge.

      the St. Louis Arch

  2. 2
    the curved part on the bottom of your foot

deep learning

a form of machine learning which incorporates the use of neural networks

BuzzWord Article

Word of the Day


meat from a young cow

Open Dictionary

snap election

a general election … that is called earlier than expected

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play